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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 18 |
| 4 | 434 |
| 5 | 2814 |
| 6 | 11127 |
| 7 | 33365 |
| 8 | 83568 |
| 9 | 184254 |
| 10 | 369254 |
| 11 | 686952 |
| 12 | 1203930 |
| 13 | 2009018 |
| 14 | 3217749 |
| 15 | 4977219 |
| 16 | 7471352 |
| 17 | 10926570 |
| 18 | 15617868 |
| 19 | 21875294 |
| 20 | 30090834 |
| 21 | 40725702 |
| 22 | 54318035 |
| 23 | 71490993 |
| 24 | 92961264 |
| 25 | 119547974 |
| 26 | 152182002 |
| 27 | 191915700 |
| 28 | 239933018 |
| 29 | 297560034 |
| 30 | 366275889 |
[0,0,18,434,2814,11127,33365,83568,184254,369254, 686952,1203930,2009018,3217749,4977219,7471352, 10926570,15617868,21875294,30090834,40725702, 54318035,71490993,92961264,119547974,152182002, 191915700,239933018,297560034,366275889] |